The present invention relates generally to electric motors with motor driver transistors and, in particular, to an electric motor with an integrated motor driver transistor.
Electric motor drivers that utilize electronic switching devices such as transistors, for control, are well known in the art. Motor driver transistors have generally been installed remotely from the electric motor to which they are connected. A typical location for a motor driver transistor is in the Electronic Control Unit (ECU) of the system of which the motor is a part. An example of such a system is an automobile ABS braking system. The ECU functions to control the operation of the system, including the operation of the electric motor which may be attached to a hydraulic pump or the like. Locating the motor driver transistor on the ECU poses a number of inherent problems, including greater difficulty in managing the electric current through the ECU. Another problem is the difficulty in dissipating the heat generated by the combined electronic components of the ECU and the motor driver transistor; the heat dissipation is necessary for the circuits of the motor driver transistor and ECU to operate within their respective safe operating zones. Yet another problem in locating the motor driver transistor on the ECU is the design condition where the power connector is located on the ECU housing. This makes the ECU housing larger in size.
It is desirable to remedy the electric current and heat load problems associated with ECUs that contain motor driver transistors. It is also desirable to reduce the size of the ECU, and further to be able to move the power connector from the ECU housing to the motor housing. It is also desirable to provide a motor diagnostic and monitoring means as part of the motor housing in order to observe the performance of the electric motor and thereby diagnose problems with motor operation.
The primary objective of the present invention is to integrate a motor driver transistor within an electric motor and thereby reduce the size and cost of the ECU. Another objective of the present invention is to integrate the power connector into the motor end plate and remove the power connector from the ECU housing, which will also reduce the size and cost of the ECU. A further objective of the present invention is to integrate a current sensing resistor and/or a motor diagnostics line with the electric motor. The ability to measure the electric motor current can enhance the performance of the motor and the electrical system of which it is a component.
The present invention achieves the objectives noted above by providing a novel electric motor end plate with an integrated motor driver transistor. By integrating the motor driver transistor as part of the motor housing end plate, the electric current control and thermal load management of the ECU can be improved.
Prior art electric motors that utilized motor driver transistors, as noted above, located the motor driver transistor remotely from the motor. The present invention incorporates the electronic switching device, or motor driver transistor, as a part of the end plate of the electric motor housing, which permits the ECU to be of a much smaller size. This novel integrated motor driver transistor allows the power connection to be moved from the ECU to the motor housing, which also permits the ECU to be of a much smaller size. In addition, the novel integrated motor driver transistor allows the motor to be fitted with at least two types of diagnostic circuits. These circuits, when connected to proper instrumentation, are able to provide better monitoring and diagnosis of the motor under operating conditions. The present invention contemplates integrating a power connector, a motor connector or both types of connectors as part of the end plate of the electric motor housing. The present invention also contemplates utilizing a field effect transistor (FET) or a bipolar junction transistor (BJT) as the motor driver transistor, but those skilled in the art will recognize that other types of electronic switching devices may be used while still remaining within the scope of the invention.
A preferred embodiment of the present invention is disclosed having an electric motor with the novel integrated motor driver transistor.
Another embodiment of the present invention is disclosed having an electric motor with the integrated motor driver transistor and an integral motor connector.
Yet another embodiment of the present invention is disclosed having an electric motor with the integrated motor driver transistor, an integral motor connector, and an integral motor diagnostics line.
Still another embodiment of the present invention is disclosed having an electric motor with the integrated motor driver transistor, an integral motor connector, and an integral current sensing resistor.